WATERFORD — The Nuclear Regulatory Commission announced Monday that it has approved a license amendment request for Unit 3 at the Millstone Power Station to increase the temperature limit for cooling water drawn from Long Island Sound from 75 to 80 degrees.

The action follows the NRC's approval in April for 80-degree water to be used at Unit 2. Millstone owner Dominion submitted the request to use the warmer water in May 2013.

Under the new limit, if the water temperature exceeds 80 degrees, Unit 3 must be placed in "hot" standby within 6 hours and "cold" shutdown within the following 30 hours.

The NRC's review of the license amendment request included an evaluation of the company's design inputs, assumptions and methodology to ensure that equipment and systems important to safety would not be harmed by the change, NRC spokesman Neil Sheehan said in a statement.

In the summer of 2012, Millstone 2 was forced to shut down for 11 days after the 75-degree temperature limit was exceeded.